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No, global warming hasn't stopped

Posted on January 20, 2013

It has become a denialist mantra: There has been no global warming for sixteen years. Any article that mentions climate change will be answered by letters and comments claiming that global warming is now over.

That’s simply not true. Anyone who says it is either seriously misinformed or willfully blind.

The argument originated with British denialist David Rose, writing in the ultra-Tory Daily Maillast Fall. He published a graph that appeared to show no warming since 1997.

As many scientists promptly proved, Rose got this result by carefully picking 1997 as his starting point. Phil Plait Bad Astronomywrote: “What he [Rose] did is like measuring how tall you are when you’re 25, doing it again when you’re 30, then claiming human beings never grow.”

But Rose was even wrong about the short term. This video, produced by the always excellent Skeptical Science, shows what really happened in the last 16 years:

This week, scientists from the NASA Goddard Institute for Space Studies (GISS) once again confirmed the temperature trend. In a paper published on January 15 (pdf), climatologists J. Hansen, M. Sato and R. Ruedy write:

“Global surface temperature in 2012 was +0.56°C (1°F) warmer than the 1951-1980 base period average, despite much of the year being affected by a strong La Nina. Global temperature thus continues at a high level that is sufficient to cause a substantial increase in the frequency of extreme warm anomalies….

“Scientists emphasize that weather patterns always will cause fluctuations in average temperature from year to year, but the continued increase in greenhouse gas levels in Earth’s atmosphere assures a long-term rise in global temperatures. Each successive year will not necessarily be warmer than the year before, but on the current course of greenhouse gas increases, scientists expect each successive decade to be warmer than the previous decade.”

For the continental U.S., 2012 was the warmest year ever. NASA GISS director James Hansen warns that there are more extremes to come:

“The U.S. temperatures in the summer of 2012 are an example of a new trend of outlying seasonal extremes that are warmer than the hottest seasonal temperatures of the mid-20th century. The climate dice are now loaded. Some seasons still will be cooler than the long-term average, but the perceptive person should notice that the frequency of unusually warm extremes is increasing. It is the extremes that have the most impact on people and other life on the planet.”

No one should expect the professional deniers to change their tune, but the science is absolutely clear. We know that global warming is real, that it hasn’t stopped, it hasn’t even slowed down. We know why it is happening. We even know how to stop it.

The only thing we don’t know is whether we can stop the climate vandals in time.